1. Field of the Invention
The present invention relates generally to systems and methods for transporting messages, and more particularly to a system and method for selectively increasing transaction costs.
2. Discussion of Background Art
Mass mailings, also known as junk mail, received through postal mail carriers is a pervasive part of most peoples lives. A desired benefit to those who originate such communications is an increase in revenues from the sale of products or services advertised in the mailing. Such physical mass mailings received by most individuals is limited, due to the transaction costs associated with their creation and mailing.
In contrast, mass e-mailings containing such advertisements are much less expensive to create and send than physical mail. As a result, the number of electronic mass mailings received by most individuals is exponentially growing, since the transaction costs are essentially mainly at the recipient's and not the sender's end. Many e-mail users receive hundreds of such junk e-mailing mailings a day. Such advertisements tend to obscure the few e-mails of real importance to a user. A term coined for such mass e-mailings is “spam.” Not only does spam waste the time of most users, it's increasingly consuming a significant amount of network bandwidth and thus is shifting some of the transaction costs to service providers as well.
There have been some proposals to deal with spam, but they have their limitations. For instance, user spam e-mail filtering programs have problems such as false hits, resulting in real messages being treated as spam, and false misses, resulting in a significant amount of spam not getting filtered out. Filtering based on approved email addresses often prevents a user from receiving desired email from people not on the list. Suing spammers for consuming network resources has largely failed, especially for spammers in other countries. Several approaches have been proposed that make spam costly. One scheme requires paying for each email and having the money refunded if the mail is accepted, but there is no agreed upon form of money that can be used. Another scheme only accepts mail if the sender can prove that an expensive computation was done, but this approach requires changes to a user's e-mail program as well as the Simple Mail Transfer Protocol (SMTP) for transporting e-mail.
In response to the concerns discussed above, what is needed is a system and method that overcomes the problems of the prior art.